US3247971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Underdrain for filter tanks
Assignee: Individual
•
Filing: 1962-04-02
•
Granted: 1966-04-26
•
Expires: 1982-04-02
Abstract
No abstract record available.
Inventors
- 👤 Richard F Kastler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:27
CPC Classifications
B; B01; B01D; B01D24/00; B01D24/02; B01D24/10; B01D24/14; B01D24/20; B01D24/24; B01D2201/00; B01D2201/04; B01D2201/0415
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-04-25 | 1969-10-25 | 1970-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-04-25 | 1973-10-25 | 1974-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-04-25 | 1977-10-25 | 1978-04-26 | $7700.00 | Window Closed / Lapsed |